1. Field of the Invention
The present invention relates generally to the field of saws for cutting stone and tile work pieces. More specifically, the present invention relates to a stone and tile saw apparatus including a circular blade, a drive motor, a saw table, a blade cooling system, a saw guard and a laterally spaced guard arm mounting assembly. The saw table has a horizontal top wall with a drive assembly housing mounted underneath including housing side walls. The table top wall is hingedly secured to and rests on the side walls.
The housing is divided by intersecting and unified motor and pulley partitions forming a combined housing partition into a blade mounting chamber and a combined blade motor and pulley chamber. The housing bottom wall extends beneath and seals the lower end of the blade mounting chamber. The motor and pulley chamber is open at the bottom for ventilation and easy access for servicing. The drive assembly includes a blade mounting bearing-loaded mandrel secured to a mandrel shelf, which in turn is secured to the housing partition within the motor and pulley chamber. A blade axle extends through the mandrel and partition and the saw blade is mounted on the blade axle within the blade mounting chamber. The blade protrudes up through a blade slot in the top wall. A pulley is secured to the blade axle within the motor and pulley chamber. A drive belt connects the blade axle pulley to a motor pulley mounted on the drive motor.
A was guard mounting arm assembly is provided including an arm fulcrum bracket mechanism secured to the table, an arm structure having a pivot end rotatably mounted to said fulcrum bracket mechanism and spaced laterally from the table and a guard end secured to the saw guard. The saw guard includes a channel member pivotally mounted to the arm structure so that the channel member is movable to various elevations over the blade while remaining in an upright orientation.
The blade cooling system includes water, or other cooling liquid, contained within the blade mounting chamber to a level that the lower portion of the blade is continually immersed. A water pump is provided in the blade mounting chamber and connected to a rubber or plastic tube extending upwardly along a housing side wall and along the lower surface of the top wall to the blade slot. The tube forks into two branch tubes and each branch tube extends to a nozzle directed toward a face of the saw blade, near the center of the blade. The pump delivers water from the blade mounting chamber to the nozzles, which spray the water onto both sides of the blade to enhance cooling and to clean debris from the blade. The rotation of the blade throws the sprayed water radially across the blade faces and to the periphery of the blade so that the water is efficiently distributed over the entire blade. The cooling system is critically important due to the high friction and resultant heat generated in the blade during stone cutting.
A drainage system is also provided. Water and debris from the blade wash over the upper surface of the top wall and into drain channels recessed into the upper surface. A series of drain holes in the drain channels pass the water from the channels through the table top wall and back into the blade mounting chamber. The upper surfaces of the housing partition extend across the entire interior of the housing and are sloped and curved downwardly to permit water and debris to slide freely to the bottom of the blade mounting chamber. Some of the drain channels are recessed along the top wall edges and also extend across the top wall, to capture the water and debris without need of upwardly extending retaining walls. An advantage of the recessed drain channels is that they do not obstruct movement of work pieces on the top wall upper surface. The saw guard inventively permits viewing of the blade, and which has a replaceable viewing panel.
2. Description of the Prior Art
There have long been stone and tile table saws having circular blades. Many have been inefficient and awkward to use.
Williams, U.S. Pat. No. 3,008,462, issued on Nov. 14, 1961, discloses a processing saw for cutting and processing rock or stone material. Williams includes a circular saw blade mounted on a saw axle extending through a mandrel. A first pulley is attached to the end of the saw axle opposite the blade and a drive belt connects the first pulley to a second pulley on a drive motor. The mandrel and motor are fastened to a mounting base. A table element is mounted over the base, on which work pieces are placed. An upper portion of the blade extends through a slot in the table element. The bottom portion of the blade extends into a vessel containing cooling water, and the rotation of the blade carries some of the water to the work piece on the table element. Drain holes are provided near the center of the table element to return water to the vessel. A problem with Williams is that water retaining walls around the periphery of the table element limit and obstruct work piece size and movement. Another problem with Williams is that the cooling water does not reach the central area of the blade, so that cooling is incomplete and blade warping may result. Moreover, water scattered on the table element must flow back to the center of the element to drain, limiting drainage efficiency. Still further problems with Williams are that debris inside the saw guard cannot be readily viewed to alert the user to the need for cleaning, and the saw guard itself can obstruct work piece movement.
Toru Naito, et al., U.S. Pat. No. 3,451,386, issued on Jun. 24, 1969, teaches an apparatus for cutting, grinding and polishing ornamental stone. Toru Naito, et al., includes a base frame having support legs. A drive mechanism is attached to the base frame and receives a drive tool. A casing is provided which surrounds the tool on the drive mechanism, and the casing has an opening for introducing work pieces. A water tank supplies cooling water to the blade through a delivery tube having a nozzle. A drainage tube at the bottom of the casing returns water to the tank. A problem with Toru Naito, et al. is that the water delivered to the blade only strikes one blade face, so that cooling is incomplete and imbalanced, and the delivery tube also obstructs user access to the blade. Another problem with Toru Naito, et al. is that the casing obstructs work piece movement during cutting and limits the size of the work piece.
Smith, U.S. Pat. No. 4,976,251 issued on Dec. 11, 1990, reveals a tile saw apparatus and method. Smith includes a cooling water tank, and a circular saw blade is mounted on an axle extending through an upper area of a wall of the water tank. The lower portion of the blade passes through the cooling water as the blade rotates. A work platform is slidingly mounted above the water tank on rails, and has a slot through which the blade passes. A channel member hinged at one end encloses the upper end of the blade to form a saw guard. A problem with Smith is that the work platform is too small to receive and maneuver large work pieces. Another problem is that the Smith saw guard does not support itself in a raised position, so that cutting thick work pieces is awkward. Mangis, U.S. Pat. No. 3,170,454, issued on Feb. 23, 1965, discloses a tile and masonry table saw. Mangis reveals a saw much like that of Smith, having blades which are partly submerged in cooling water within a compartment beneath the table top.
Wain, U.S. Pat. No. 4,080,952, issued on Mar. 28, 1978, discloses a cooling oil reservoir and a circular saw blade rotatably mounted on the reservoir so that the lower portion of the blade is immersed in the oil. A motor drives the saw blade with a belt and pulleys, and a channel member extends around a lateral edge of the blade to form a shroud for directing the cooling oil picked up by the blade into the cut made in a stone work piece. A problem with Wain is that there is no convenient way to position and hold a work piece, which must be engaged above the shroud. Wain also apparently fails to provide means for preventing the cooling oil from splashing on and otherwise accumulating on the drive belt and drive motor.
Crocetti, U.S. Pat. No. 4,779,603, issued on Oct. 25, 1988, teaches a brick saw container. A saw is mounted to an arm above a work table, and the table is enclosed on three sides by a housing. Water piping delivers water to the blade through opposing sides of a channel-shaped saw guard suspended over the top of the blade. A problem with Crocetti is that the enclosure and the saw guard both substantially obstruct movement and positioning of a work piece, such as during cutting of a U-shaped bottom connection. Both also limit the size of the work piece Crocetti can accept.
Bein, U.S. Pat. No. 4,107,883, issued on Aug. 22, 1978, teaches an apparatus for controlling feed mechanisms of grinding and cutting apparatus. Bein is essentially a box containing a vice for gripping a work piece to be cut by a circular saw blade. The sides of the vice and the box limit the size of the work piece Bein can accept, and completely inhibit movement of the piece necessary to making many types of cuts.
It is thus an object of the present invention to provide a stone and tile cutting table saw apparatus having a liquid cooled blade driven by a belt from a motor in a separate compartment, so that the motor is kept dry.
It is another object of the present invention to provide such an apparatus having a blade which reaches the work piece from underneath so that no corner bur remains in a cut when the cut appears from the top to be complete. The end of the cut curves into the scrap piece rather than out at the bottom of the cut.
It is another object of the present invention to provide such an apparatus including a saw guard which can be positioned at various elevations above the blade to accommodate work pieces of various thicknesses, which remains substantially level at these various elevations, which has a replaceable blade viewing section, and which is mounted on a support assembly spaced laterally from the table and is pivotable to maximize work piece movement and accommodated size range.
It is still another object of the present invention to provide such an apparatus which distributes cooling fluid over virtually the entire surface of each blade face, rather than merely along the blade periphery, for complete cooling and longer blade life.
It is still another object of the present invention to provide such an apparatus in which there is no saw mounting arm protruding upwardly from a side of the table to obstruct work piece movement during cutting.
It is finally an object of the present invention to provide such an apparatus which is reliable, easy to service and economical to manufacture.